Various tube to header connections have been proposed to provide a leak proof strong connection between tube passes and header tanks of heat exchanger assemblies such as radiators, evaporators, condensers and the like.
An example of one form of such tube to header connections is shown in U.S. Pat. No. 3,027,142. It has a header tank with a wall formed with a tube portion forming a support for the end of a tube pass. The tube pass is rolled against an O-ring to seal the tube to header joint.
British Patent 1232414 dated May 2, 1969 discloses a heat exchanger having a flat tube formed with circular ends or round ends that are deformed by metal spinning to be engaged with frustoconical surfaces formed in a header wall. A layer of adhesive is applied to the circular end portion prior to the metal spinning step to seal against leakage at the joint.
U.S. Pat. No. 4,825,941 discloses a condenser type heat exchanger having flat tubular elements with interposed heat exchanger fins sandwiched therebetween. Ends of the tubular elements are seated in a header slot and a brazed joint is formed at the interface between the ends of the tubular elements and the header.
While each of the aforesaid heat exchangers are suitable for there intended purpose they do not disclose how to form a bonded joint between a flattened tube pass and a header tank which will have an extended contact surface for improved bonding while assuring that the tube end of the flattened tube pass will extend into the header a controlled distance which will not interfere with fluid flow between inlet and outlet fittings of an associated system. More particularly, in the heat exchanger in the '142 patent the seal requires a separate gasket or a separate O-ring seal and it also requires that the end of the tube be rolled over to provide a mechanical connection between the header wall and the tube pass. The British Specification discloses a heat exchanger or radiator that requires that flat tube segments be formed to have circular end portions and further requires that the circular ends be deformed by metal spinning to seal against the header. The header walls must be fixtured with respect to the ends of the tube to assure that the tube ends are properly positioned for spinning connection to the header. Likewise the '941 patent must have the extruded tubes therein fixtured to form a desired connection between the header and the flattened tube.
In none of the aforesaid arrangements is there a provision of an inclined or tapered contact surface on the tube and header which combine to define an extended surface for forming a high strength brazed connection between a tube pass and the wall of an associated header component in a heat exchanger assembly. Furthermore, none of the aforesaid arrangements provide a shoulder surface for located the tapered surfaces to control the tube stickout length within the header volume.